I used exactly that strategy against the elite 4 in my first white playthrough and man does it rock with a quiet nature or modest for that matter.It it an awesome wall and can get 105 (104.5) sat with +sat natures then just EV train it more to probably get it up to 120 ish. man it it seriously worth anyone's while

if you make contact with a pokemon with this ability your ability will be changed to this and it will pretty much keep spreading to other pokemon. (as long as they make physical contact.) the ability itself doesn't do any thing